DE1773200C3 - Piezoelectric measuring device - Google Patents

Description

engines given.

_a5 The invention now pursues the goal of a measuring device that is also suitable for high thermal loads.

The invention relates to a piezoelectric measuring device of the aforementioned A.rt ™ ^sc ™ · J «device for measuring the combustion chamber pressure in from a particular £. This Au _c abc-making and; .st tuned ^AH1 ™ "^ the cylinders of a water-cooled Brennnkraftma- and specifically to the _f ^{E 'ns} ^. ^ ^ / ^ USE machine, with a the transducer thermally conductive environmentally 30 motors to Losuiig. is aufwei- cooling surfaces on its periphery inventively provided that ^ you. good send sleeve ζ in a heat-conducting water-cooled WALLS material. BA ¹ "™"^"1 ™ · ^best to the cylinder head surrounded in-Jizierbohrung immediate sleeve as Dchnhülse The starting point is that it can be screwed in * smooth cylindrical jacket surface on the inner wall

Piezoelectric measuring devices of this type are in contact with the indexing hole, with ^ ^dl ^ ^Delin I "' ⁵ " J "being exposed to high temperatures during measuring operation and an internal thread, η de necessary for the reception, otherwise thermal expansion occurs constructive tion uses the existing naturhch _c tempera vision. In the field of high temperatures makes turdifferenz between the Meßwandi _cr una "" gT also against the Curie temperature rapidly abfal- cooled inner wall of the Indizie ^ tion for from c.-lcnde sensitivity of piezoelectric Critical to measure the excess heat, so that it can cause a considerable disruptive effect on the knife noticeable 45 reaching cooling of the sensitive measuring wall it

^ε It is ™ known; the heat load of such measurement certainties. By the contact pressure to reduce the mtds converter characterized in that expanded in the expansion cone Dehn Wandlerge- the sleeve ^ e rue n dwell cavities are provided which n.sst to a particularly favorable in ^{bc Wa} ™ 7 L8 ^a "S ^ ^ld 'own The between the Dchnhülse and ^d . ^Cr ^ ''"^ ⁰ ^ ³ⁿ T effort for such a Kühlwasscrsystcm with Was- ₅ o dung created. E.ne measuring device of this Ar J ₁ water pump, a multitude of lines and the especially for application bc. large, what ^ different control devices for the temperature engines gcc.gnet in which the cylinder head and flow rate control is relatively large and a considerable height aul therefore only appears for the purposes of research and the invention is hereinafter referred to in

Development justified. Such cooling systems have to nose 55 of the drawing illustrated embodiment also described to avoid premature prediction. The only figure shows an axial limestone the transducer with distilled water cut after a piezoelectric measuring device be driven, a measure that resulted in the redeeming of the invention.

gel only with stationary measuring devices as a practical The only partially shown, a Kunlwasscr-

drove too little operationally reliable. 60 cylinder head 24 containing space 23 has a

In the case of transducers, which are used in continuous operation, indexing bore 25 with a threaded part 26 aut, for motor monitoring purposes, the threaded shaft of a Dennhulse 27 is made of well which means the considerable expense for the heat-conducting material is screwed in. The cooling device has a serious disadvantage. The sleeve 27 has a smooth, cylindrical sleeve. In addition, such Kiihlwasscrsystemc 6 ₅ tclflächec 28 and is on the side facing away from the screw a relatively large amount of space and are not operationally safe enough for the permanent side with two longitudinal gaps. give away. The Dchnhülse 27 has a stepped

In the case of a transducer, which is provided with a blind hole 30 with an internal thread 31 for

Receiving the piezoelectric transducer 9 and a threaded part 3; S of larger diameter for receiving an expanding cone 33 which can be introduced into the indexing bore 25. By tightening the expansion cone 33, the expansion sleeve 27 is expanded radially and its cylindrical jacket surface 28 is pressed against the inner surface of the indexing bore 25. This leads to an intensive heat exchange between the transducer 9, which is heated by the combustion gases, and that on the inside. side of the wall of the cylinder head 24 flushed by the cooling water. The contact pressure of the expansion sleeve 27 ensures extensive contact and thus favorable heat transfer conditions.

1 sheet of drawings

Claims (1)

use of the longUudmalen Elasto-resistance fckts worked, has also already been proposed. Claim: fckts Piezoelectric measuring device mv measurement to «mfossen and the wipe ^« yyy » ZmSm of the combustion chamber pressure in the cylinders of a 5 |" ^ _t g ^ ^e ^ ⁿ , S on the circumference of the sensor water-cooled internal combustion engine, with a 5F ^chst ™ ^m _p ^e "r _e / _e ⁰ Sen are doing the Wärmeden transducer thermally conducting comprehensive and house ^ "jS ^ hKum favor. If having on its periphery cooling surfaces transition ^ / ^d ^ _t ™ XdensteIlende cooling sleeve into a water-cooled walls and in this way a zui _be the indexing hole surrounding the cylinder head i. of the transducer f "™} ™ ^" ^ "^ _dem / ^^^ can be screwed in and to accommodate a piezo-electric transducer ,, durchgeke η η ζ eich η et that they are made of good, in purchase S ^cno ^ _h ⁿ _{nm soaps} _ _Dnlckge over heat-conducting material existing sleeve (27) values «« ^ * gjg «sevoSsetttes is designed as an expansion sleeve, whose smooth ψη- χ ₅ ^ \ ^d f ^r _P S, ^ _u ^ _t Elches on the circumference with a drical surface (28) on the inner wall of the wL ^ «* gJ cooling measures on the indexing hole (25), and that the expansion cooling ribs besrtet «V ^ ™^. ^. _{But only then as a} sleeve on the side facing away from the measuring point, a ^Dn ^^ ^te .f3dSr heat exchange longitudinal expansion gap (29) and an internally effective ™« ^ lu ™ taÄm SSrfufWrom thread (32) for receiving One of the screwdrivers is at most a spre.zkonus (3 ”has. Grayling types of air-cooled engines, however only in exceptional cases with water-cooled fuel